1. Technical Field
This document relates to compounds as well as methods and materials involved in modulating neurotransmitter reuptake.
2. Background Information
Neuronal signals are transmitted from cell to cell at specialized sites of contact known as synapses. The usual mechanism of transmission is indirect. The cells are electrically isolated from one another, the pre-synaptic cell being separated from the postsynaptic cell by a narrow synaptic cleft. A change of electrical potential in the pre-synaptic cell triggers it to release signaling molecules known as neurotransmitters. The neurotransmitters rapidly diffuse across the synaptic cleft and provoke an electrical change in the postsynaptic cell by binding to neurotransmitter receptor-gated ion channels. After release, the excess neurotransmitters are rapidly removed, either by specific enzymes in the synaptic cleft or by reuptake into the pre-synaptic cell or surrounding glial cells. Reuptake is mediated by a variety of neurotransmitter transporters. Rapid removal ensures both spatial and temporal precision of signaling at a synapse. For example, rapid reuptake can prevent excess neurotransmitters from influencing neighboring cells and can clear the synaptic cleft before the next pulse of neurotransmitter release so that the timing of repeated, rapid signaling events is accurately communicated to the postsynaptic cell.
An imbalance of neurotransmitters in the brain can occur when not enough neurotransmitter is made and released from pre-synaptic cells or the reuptake of neurotransmitters by pre-synaptic cells is too rapid. If neurotransmitters such as serotonin, norepinephrine, or dopamine are not made and released in effective amounts or are cleared from the synaptic cleft too quickly, then cell-to-cell communication can be affected. Clinical manifestations of such imbalances include depression and anxiety disorders. Serotonin-, norepinephrine-, dopamine-reuptake inhibitors (SNDRIs) represent a class of potent, wide-spectrum antidepressant medications that inhibit the reuptake of these neurotransmitters back into pre-synaptic cells. Inhibiting neurotransmitter reuptake can increase the amount of neurotransmitter present in the synapse, thus helping to normalize the transmission of neuronal signals and alleviate the symptoms of depression and anxiety disorders.